Selective twin filter mechanism and method for dry cleaning mechanism



Dec. 13, 1966 D. L. ANDERSON 3,291,562

SELECTIVE TWIN FILTER MECHANISM AND METHOD FOR DRY CLEANING MECHANISM Filed May 2'7, 1963 fi olo A INVENTOR. Dam M7 Jami/M91350 27 /.9& BY

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United States Patent Ofifice 329L552 Patented Dec. 13, 1966 SELECTIVE TWlN FILTER MECHANISM AND METHOD FOR DRY CLEANING MEtIHANISM Doyle L. Anderson, Cnpertino, Califi, assignor to Selfervice Machines, Inc, Santa Clara, Calif., a corporation of California Filed May 27, 1963, Ser. No. 283,335 8 Claims. (Cl. 8-142) The present invention relates to coin operated dry cleaning mechanisms, and pertains more particularly to an improved, selectively actuated, twin filter mechanism and method for filtering dry cleaning solvent.

Until quite recently, the dry cleaning of clothes, drapes and other fabric articles has been practice principally by professional dry cleaning establishments, where the customer leaves clothing to be cleaned, and picks it up or has it delivered when completed.

Now, however, there is a rapid increase in the installation and use of coin operated dry cleaning establishments, wherein a plurality of coin operated automatic dry cleaning machines are provided, and wherein the cus tomer brings in the articles to be cleaned and either places them in one of the machines himself, or turns them over to an attendant for so doing. The attendant usually performs any specialized spot-tin operations that may be required.

After a load of specified maximum weight, for example eight pounds, has been placed in a machine, the machine is then actuated by depositing the required fee, for example two dollars. The machine then automatically initiates and completes its programmed cleaning and drying cycle, employing a suitable cleaning solvent, such as, for example trichloethylene or perchlorethylene.

In the performance of the cleaning cycle a substantial quantity of dirt solids is removed from the clothing or other articles being cleaned, as well as some dye coloring and fatty acids resulting from the removal of grease and perspiration.

For removing the dirt solids, it is common practice to recirculate the solvent employed through a suitable filter, such as a fiber type filter, or one containing diatomaceous earth. The dye coloring is removed by passing the filtered solvent through a tank containing a de-colorizing agent, such as activated carbon, and suitable means are also provided for removing the fatty acids.

A typical cleaning cycle of such a machine comprises an initial Wash period of approximately five minutes, which includes the filling of the cleaning chamber in which the clothes are cleaned, and a later rinse cycle, which also includes a filling of the cleaning chamber. When the filter is clean, the solvent fiows freely therethrough, so that it requires only about one and one-half minutes to fill the cleaning chamber. In such case an adequate volume of solvent is present during the major portion of the cleaning and rinse cycles. When the filter becomes clogged with removed dirt solids, however, it restricts the flow of solvent to the cleaning chamber to such an extent that most or all of the wash and rinse periods are required simply to fill the cleaning chamber. This of course leaves insufiicient time for doing a thorough cleaning job.

The complete cycle, which includes, in addition to the wash and rinse periods, the usual spin or solvent recovery and final drying periods, generally requires between 25 and 45 minutes per load. Except during filling of the cleaning chamber, during which time the filling valve is open, the solvent is recirculated continuously from a storage reservoir through the filter and de-colorizer so as to prepare the solvent for the next load of articles to be cleaned.

During the recirculating period following each closing of the filling valve, and lasting until the latter opens again,

it is not important that the rate of flow be high. In fact, even a filter so dirty as to be unuseable during the filling period would be suitable for such interim use. In order to provide a free flow of solvent into the cleaning chamber during the filling and rinse periods, it is customary to replace the filters long before they become unsuitable for use during the recirculating or between filling portions of the cycle. In the past numerous attempts have been made to improve the filters and to extend their life. Such exped-ients have, however, usually resulted in more complex and expensive mechanisms, and in a substantial increase of installation and maintenance costs.

The present invention provides, in a dry cleaning mechanism, improved performance and extended filter life by selective use of a pair of filters, one of which, the main filter, is constantly open for the circulation of solvent from the storage reservoir through the main filter and the de-colorizer back to the storage reservoir, while the second or reserve filter is opened to such flow only during the filling portions of the cycle, and, in one form of the invention, when the main filter becomes so clogged as to prevent an adequate solvent flow even during non-filling portions of the cycle. Thus, the main filter performs the major portion of the filtering operation, while the reserve filter is cut into the line during filling portions of the cycle, and after the solvent has already been subjected to a filtering operation by the main filter.

Another object of the invent-ion is to provide, in a dry cleaning mechanism, a pair of filters connected in parallel to receive solvent pumped under pressure from the storage reservoir of such mechanism through said filters and thence either back to the storage reservoir or to a filling valve, one of the filters being open to such circulation at all times to filter such solvent, the other filter being closed to such circulation except when the pressure in the line from the main filter to the storage reservoir and to the cleaning chamber filling valve drops below a pre set minimum.

A further object of the invention is to provide an improved, selective, twin filter mechanism and method for a dry cleaning system.

These, and other objects and advantages of the invention, will be apparent from the following description and the accompanying drawings, wherein:

FIG. 1 is a diagrammatic view showing a coin controlled dry cleaning mechanism embodying the present invention. 7

FIG. 2 is a fragmentary view showing a modified form of the invention from that shown in FIG. 1, the right hand 7 portion of the mechanism of FIG. 2, which is similar to the right hand portion of FIG. 1, being broken away.

FIG. 3 is a schematic diagram showing a circuit for actuating the valves which selectively control the circulation of solvent through the reserve filter and the carbon tank as shown in FIG. 1.

FIG. 4 is a similar type of diagram, but showing a circuit for controlling the valves as arranged in FIG. 2.

Briefly, the form A of the invention shown in FIG. 1 comprises a conventional cleaning chamber 10, filling valve 11, dump valve 12, solvent storage reservoir 13,

Q pump 14, de-colorizer or carbon tank 15, and. a pair of filters 17 and 18. A line 19 communicates the main filter 17 with the filling valve 11, while a branch line 20, having a biased restriction 21 therein, communicates the line 19 with the carbon tank 15.

from the filling valve 11. Thus, during each filling period,

a parallel How of solvent is permitted through both filters 17 and 18 and thence through the filling valve 11 into the cleaning chamber 19', while the flow of solvent to the carbon tank 15 is shut off during such period. During the non-filling periods of pump operation, the main filter 17 alone performs the filtering operation, and operates continuously from each closing of the filling valve 11 until the next opening thereof.

An additional feature of the invention resides in the optional, but preferred, provision of a pressure sensitive switch 27 (FIGS. 2 and 4) in the line 19 for cutting in the reserve filter 18 upon each pressure drop in the line 19 below a pre-set minimum. This feature of the invention provides advantages which will be described more fully later herein.

Referring to the drawings in greater detail, the form A of the invention shown in FIGS. 1 and 3 comprises a usual cleaning chamber 10, which may be of any suitable type. A number of such machines are well known, and are available commercially, and since the details thereof are not a feature of the present invention it will be unnecessary to illustrate or describe them herein.

The filling valve 11 may be a conventional, spring closing solenoid valve, and solvent flowing therethrough is discharged into the inlet 28 of the cleaning chamber 10. A conventional overflow line 29 and dump line 30 are provided from the cleaning chamber 10, and discharge into the solvent storage reservoir 13 through a screen 31. The latter screens out any article such as buttons, safety pins, lint balls etc. which may pass through the dump line 30. The flow of solvent through the dump line 30 is controlled by the solenoid valve 12, which is electrically connected to the usual programming or timing switch (not shown) which controls the sequence and duration of the various portions of the cycle of operation of the mechanism A. Since such programming or timing switch is an integral part of the dry cleaning mechanism, and since its details are well known, and are not material to the present invention, it is neither illustrated nor described herein.

From a low point in the storage reservoir 13 a supply line 32 communicates with the inlet of the pump 14, which may be the pump of the dry cleaning mechanism A. The pump outlet communicates, through a branched line 33, with the inlets 34 and 35 of the two filters 17 and 18. These filters may be of any suitable type, and as illustrated each comprises a housing 37, filter cartridge 38, and perforated axial return tube 39, which communicates with the outlet 36 from the housing 37. The de-colorizer, which is illustrated as a conventional carbon tank 15 is provided with a quantity of activated carbon 41 retained therein between foraminous or porous re taining screens 42 and 43. The type of de-colorizer employed is not material to the invention, and if desired decolorizing material may be incorporated in the filters, or elsewhere as desired. If no de-colorizer is provided in the line 20, then the return line from the main filter 17 to the storage reservoir 13 would still be provided with suitable biased flow restricting means such as the element 21 to place the solvent in the return line under desired pressure during an adequate non-filling circulation flow of the solvent.

A by-pass line 47 communicates the line 20, ahead of the biased flow-restricting element 21 therein, with the storage reservoir 13. The by-pass line 47 also has a biased flow-restricting element 48 therein, with a greater restrictive bias than the flow-restricting element 21. These flow-restricting elements 21 and 48 may be spring biased flow-restricting valves of a suitable or well known type. Thus, as long as pressure in the line remains above the releasing pressure of the flow restricting element 21, and below the releasing pressure of the flow restricting element 48, solvent will flow through the line 20, the carbon tank 15 and a drain line 49 back into the storage reservoir 13. Should, however, the pressure in the line 20 become greater than the releasing pressure of the bypass fiow restricting element 48, then excess solvent will be released by the latter element and will be by-passed through the line 47 to the storage reservoir 13.

From the outlet of the reserve filter 18 the line 24 communicates, through the valve 23, with the line 19 from the main filter 17. All of the valves illustrated may be conventional, spring-closing, solenoid valves, although neither the type of valve employed, nor the means for actuating them are features of the invention. 1

A circuit for controlling the valves 11, 23 and 25 of the arrangement shown in FIG. 1 is illustrated in FIG. 3. Two conductor wires 51} and 51 may be the line conductors leading to the filling valve switch contacts 52 of the usual timing or programming switch (not otherwise shown) of the dry cleaning mechanism A.

With the switch contacts 52 closed, the line conductors 5t) and 51 are connected in parallel to the windings of the two solenoid valves 11 and 23, and also to the winding of a normally closed relay 53. The latter controls the flow of electricity through a pair of conductors 55 and 56 to the winding of the carbon tank supply line solenoid valve 25.

The operation of the form of the invention shown in FIG. 1 is as follows:

Assuming that an adequate supply of solvent is present in the storage reservoir 13, that the dry cleaning mechanism A is properly connected to a suitable supply of electricity, and that the pump 14 is operating at a required speed; during the time that the switch contacts 52 are closed, the filling valve 11 is open, as is also the reserve filter control valve 23, while the valve 25 in the carbon tank supply line 20 is closed. In this condition of the valves 11, 23 and 25, solvent is drawn from the storage reservoir 13 by the pump 14, and is supplied under pressure to the branched line 33. Thence it flows through both filters 17 and 18 in parallel, and through the lines 19 and 24 and the filling valve 11 into the cleaning chamber 10. The closed valve 25 in the line 20 to the carbon tank prevents any flow of solvent to the carbon tank during such filling period, which might detract from the flow to the filling valve.

Upon completion of the filling operation, the switch 52 opens, in its usual manner, de-energizing the switches 11 and 23 and the relay 53. This action allows the filling valve 11 and reserve filter control valve 23 to close, and the valve 25 to the carbon tank 15 to open. This condition of the valves 11, 23 and 25 causes a flow of solvent from the storage reservoir 13, through the pump 14, the main filler 17 only, the line 19, the line 20 and thence through the carbon tank 15, and also, in case of excess pressure in the line 20, through the by-pass line 47, back into the storage reservoir 13.

In the modified form of the invention shown in FIGS. 2 and 4, the various parts of the mechanism, including the valves and piping, are generally similar to those illustrated in FIG. 1. Corresponding parts of the mechanism of FIGS. 2 and 4 are, therefore, designated by the same reference numerals as those employed in FIG. 1, with the suifix a added thereto. The right hand portion of the dry cleaning mechanism, which is broken away in FIG. 2, may be considered as identical to that shown in FIG. 1.

The difference between the structure, circuitry and operation of the mechanism shown in FIGS. 2 and 4 and that shown in FIGS. 1 and 3, resides in the fact that, instead of the reserve filter control valve 23a being connected to operate synchronously with the filling valve 11a, it is controlled by the normally closed, pressure sensitive switch 27. This switch 27 is provided with a suitable pressure sensitive element, such as for example, a conventional bellows 57, which is exposed to the interior of the line 19a from the main filter. This pressure sensitive element is lightly spring biased toward a closed condition of the usual switch contacts 58 thereof.

When the pressure sensitive element 57 of the switch 27 is subjected to a pre-set minimum pressure by the solvent in the line 19a, it opens the switch contacts 58, and thereby allows the reserve filter control valve 23a to close. -When, however, the pressure of the solvent in the line 19a drops below such pre-set minimum pressure, the switch contacts 58 are thereby permitted to close, and thereby complete a circuit through the winding of the solenoid valve 23a to open the latter valve and permit a flow of solvent through the reserve filter.

A signal light 59 is preferably connected in series with the pressure sensitive switch 27, so that when the latter is closed the light 59 will light, and when the switch 27 is open the light is extinguished. However, it will be noted that if a condition of low pressure in the line 19a which causes the light 59 to light is caused by a clogged main filter during a non-filling period of operation, as soon as the switch 27 closes, thereby causing the light 59 to light, it also opens the valve 23a, thereby permitting a free flow of solvent through the clean reserve filter. This free solvent flow will immediately raise the pressure in line 19a and extinguish the light. Thus, when the main filter becomes so clogged as to prevent a required flow of solvent during non-filling periods of operation, this condition will be made apparent through the flashing of the light 59.

Unless means are provided to prevent it, such as a relay like that 53a for the carbon tank control valve 25a, the light 59 will alway be lighted continuously during each filling operation, during which time the pressure in the line 19a is relieved by the open filling valve 11a.

In either of the illustrated forms of the invention, the filtering element such as the cartridge 38 of the reserve filter 1 8 should be renewed or replaced with a fresh one after several main filter filtering elements have been replaced, at which time the old reserve filtering element, which will still be quite clean, may be used in the main filter. Otherwise, by a simple valve arrangement, which will be obvious to any ordinarily skilled service man or engineer, a suitable valve which may be similar to those illustrated, may be placed in the line 19 from the main filter, and by a simplevalve reversal, upon the renewing or replacing of each main filtering element with a fresh one, the latter may then 'become the new reserve filtering element, while the former main filter becomes the reserve filter. In that way, by a slight increase in installation cost, it will never be necessary to change more than one filter at a time.

The invention provides a simple, inexpensive, efficient and highly effective mechanism for controlling the flow of solvent through two filters .in such a way that each filter is used throughout its maximum possible life, while at the same time always providing a fresh, clean, unobstructed filter for use during each filling cycle.

While I have illustrated and described a preferred embodiment of the present invention, and one modified form thereof, it will be understood, however, that the dry cleaning mechanism with which the invention is used is not necessarily of the coin controlled type, and that various changes and modifications may be made in the details of the invention without departing from its scope as set forth in the appended claims.

Having thus described the invention, what I claim as new and desire to protect by Letters Patent is defined in the following claims:

1. A twin filter mechanism for a dry cleaning mechanism having a plurality of filling cycles and an interim recirculating cycle between successive filling cycles, and having a cleaning chamber with a filling valve therefor, a storage reservoir for receiving solvent discharged from the cleaning chamber, and a pump having an inlet and an outlet with its inlet communicating with a low point of the storage reservoir, the pump operating during both the filling and recirculating cycles, said twin filter mechanism comprising:

(a) a pair of filters, each having an inlet and an outlet,

(b) a branched line connected from the pump outlet to the inlet of each filter,

(c) a common line communicating the outlets of both filters with the filling valve of the cleaning chamber, and

(d) automatic valve means operating synchronously with the filling valve and operatively controlling the flow of solvent from the pump through one only of the filters for automatically closing said valve means for shutting off the flow of solvent from the pump through said one filter during each recirculating cycle when the filling valve is closed, andfor automatically opening said valve means for allowing a free flow of solvent from the pump through both filters to the filling valve during each filling cycle when the filling valve is open.

2. A twin filter mechanism for a dry cleaning mechanism having a plurality of filling cycles and an interim recirculating cycle between successive filling cycles, and having a cleaning chamber with a filling valve therefor, a storage reservoir for receiving solvent discharged from the cleaning chamber, and a pump having an inlet and an outlet with its inlet communicating with a low point of the storage reservoir, the pump operating during both the filling and recirculating cycles, said twin filter mechanism comprising:

(a) a pair of filters, each having an inlet and an outlet,

(b) separate lines connected from the pump outlet to the inlet of each filter,

(0) separate lines communicating the outlets of both filters with the filling valve of the cleaning chamber, and

((1) pressure sensitive flow control means operatively controlling the flow of solvent from the pump through one only of the filters, and exposed to pressure within the line from the outlet of the other filter to the filling valve, said flow control means being automatically actuated to shut off the flow of solvent from the pump through said one filter when the pressure in the line from the outlet of the other filter to the filling valve is raised upon closing the filling valve, and being again automatically actuated to allow a free flow of solvent from the pump through both filters to the filling valve when the latter is opened to reduce the pressure in the line from the outlet of the other filter to the filling valve.

3. A twin filter mechanism for a dry cleaning mechanism having a plurality of filling cycles and an interim recirculating cycle between successive filling cycles, and having a cleaning chamber with a filling valve therefor, a storage reservoir for receiving solvent discharged from the cleaning chamber, and a pump having an inlet and an outlet with its inlet communicating with a low point of the storage reservoir, the pump operating during both the filling and recirculating cycles, said twin filter mechanism comprising:

(a) a pair of filters, each having an inlet and an outlet,

(b) a line connected from the pump outlet to the inlet of each filter,

(c) a line communicating the outlet of each filter with the filling valve of the cleaning chamber,

((1) means for providing a restricted circulation of solvent by the pump when the filling valve is closed,

(e) a valve controlling the flow of solvent from the pump through one only of the filters,

(f) and means operatively interconnecting the latter valve with the filling valve automatically operating both of said valves in synchronism with each other,

whereby said latter valve closes off the flow of solvent from the pump through said one filter during the restricted flow of solvent when the filling valve is closed, and allows a free flow of solvent from the pump through both filters to the filling valve when the latter is open.

4. A twin filter mechanism for a dry cleaning mechanism having a plurality of filling cycles and an interim recirculating cycle between successive filling cycles, and having, a cleaning chamber with a filling valve therefor, a solvent storage reservoir for receiving solvent discharged from the cleaning chamber, and a pump having an inlet and an outlet with its inlet communicating with a low point of the storage reservoir, the pump operating during both the filling and recirculating cycles, said twin filter mechanism comprising:

(a) a pair of filters, each having an inlet and an outlet, (b) a line communicating the pump outlet with the inlet of each filter, (c) a line communicating the outlet of each filter with the filling valve, (d) a valve for controlling the flow of solvent through one of the filters, (e) a by-pass line communicating the lines from the filters to the filling valve with the storage reservoir, (f) a biased restriction in the by-pass line for increasing the pressure of solvent Within the line communicating the other filter with the filling valve through the by-pass line, and (g) pressure sensitive means exposed to the pressure within the line communicating the other filter with the filling valve, and operatively connected to the valve for controlling solvent flow through said one filter to automatically close the valve thereby shutting olf the fiow of solvent through said one filter upon an increase of pressure on the pressure sensitive means above a pre-set minimum, and to automatically open the valve thereby allowing a flow of solvent through said one filter upon a decrease in pressure on the pressure sensitive means below such pre-set minimum. 5. The method of prolonging filter life and insuring a full fiow of solvent during the filling period of a dry cleaning mechanism having a plurality of filling cycles and an interim recirculating cycle between successive filling cycles, and having a cleaning chamber with a filling valve therefor, a storage reservoir, and a pump actuated, solvent circulating system operating during both the filling cycles and the recirculating cycles; which method comprises passing the circulating solvent under pressure to a pair of parallel filters in the solvent circulating system automatically, closing oil the 'flow of solvent through one of the filters during each recirculating cycle when the filling valve is closed, and automatically opening the flow of solvent through both filters during each filling cycle when the filling valve is open.

6. The method of prolonging filter life and insuring a full flow of solvent during the filling period of a dry cleaning mechanism having a plurality of filling cycles and an interim recirculating cycle between successive filling cycles, and having a cleaning chamber with a filling valve therefor, a storage reservoir, and a pump actuated, solvent circulating system having a biased restriction in a by-pass return line to the storage reservoir, said solvent circulating system operating during both the filling cycles and the recirculating cycles; which method comprises passing the circulating solvent under pressure to a pair of parallel filters in the solvent circulating system'automatically closing oil one of the filters to the flow of solvent therethrough during the recirculating cycle when the pressure in the return line is above a pre-set minimum, and automatically opening said one filter to the flow of solvent therethrough during the filling cycle when the pressure in the return line drops below such pre-set minimum.

7. A twin filter mechanism for a dry cleaning mechanism having a plurality of filling cycles and an interim recirculating cycle between successive filling cycles, and having a cleaning chamber with a filling valve therefor, a solvent storage reservoir for receiving solvent discharged from the cleaning chamber, a line communicating a low point of the storage reservoir with the filling valve, a pump in the line for drawing solvent from the storage reservoir and supplying it underpressure to the filling valve for discharge into the cleaning chamber, and a bypass having -a biased restriction therein communicating the line beyond the pump with the storage reservoir, the pump operating during both the filling and the recirculating cycles:

(a) a pair of filters connected in parallel into the line ahead of the by-pass,

(b) a filter control valve controlling the flow of solvent through one only of the filters,

(c) and means operatively connected to the filling valve and to the filter control valve automatically operating both of the valves substantially synchronously,

whereby, When the filling valve is opened, the filter control valve is also opened to provide a parallel fiow of solvent through both filters, and when the filling valve is closed, the filter control valve is also closed to thereby provide a flow of solvent through the other filter only.

8. An arrangement according to claim 7 wherein the valve operating means operatively connected to the filling valve and the filter control valve is automatically respon sive to selected changes to pressure in the line at a point between the other filter and the filling valve.

References Cited by the Examiner UNITED STATES PATENTS 555,855 3/1896 Fleetwood 210- 2,316,669 4/1943 Busi 8142 X 2,423,329 7/1947 LeClair 210-137 X 2,757,801 8/1956 Muggli et a1 21090 2,836,045 5/1958 Smith 2l0-167 X 2,854,140 9/1953 Muller 210-90 2,912,110 11/1959 Stoltenberg 2l0l67 3,203,754 8/1965 Young et al. 210l67 REUBEN FRIEDMAN, Primary Examiner.

SAMIH N. ZAHARNA, Examiner.

J. DECESARE, Assistant Examiner, 

5. THE METHOD OF PROLONGING FILTER LIFE AND INSURING A FULL FLOW OF SOLVENT DURING THE FILLING PERIOD OF A DRY CLEAINING MECHANISM HAVING A PLURALITY OF FILLING CYCLES AND AN INTERIM RECIRCULATING CYCLE BETWEEN SUCCESSIVE FILLING CYCLES, AND HAVING A CLEANING CHAMBER WITH A FILLING VALVE THEREFOR, A STORAGE RESERVOIR, AND A PUMP ACTUATED, SOLVENT CIRCULATING SUSTEM OPERATING DURING BOTH THE DILLING CYCLES AND THE RECIRCULATING CYCLES; WHICH METHOD COMPRISES PASSING THE CIRCULATING SOLVENT UNDER PRESSURE TO A PAIR OF PARALLEL FILTERS IN THE SOLVENT CIRCULATING SYSTEM AUTOMATICALLY, CLOSING OFF THE FLOW OF SOLVENT THROUGH ONE OF THE FILTERS DURING EACH RECIRCULATING CYCLE WHEN THE FILLING VALVE IS CLOSED, AND AUTOMATICALLY OPENING THE FLOW OF SOLVENT THROUGH BOTH FILTERS DURING EACH FILLING CYCLE WHEN THE FILLING VALVE IS OPEN. 